Videotape recording and playback device, and videotape player

ABSTRACT

The object of the present invention is to reduce the load and specification requirements on the network and the video server. The buffer usage rate is counted and supplied to the tape driving controller  7 . In the reproduction mode, the tape driving controller  7  decreases the running speed of a video tape when the buffer usage rate is larger than the proper value. And when the buffer usage rate is smaller than the proper value, the tape driving controller  7  increases the running speed of the video tape. Moreover, in the recording mode, the tape driving controller  7  stops the tape motion temporarily if the transmission speed of the network is slow and the buffer usage rate declines lower than the proper value. And if the buffer usage rate increases over the proper value, the tape driving controller  7  resumes the tape driving to record signals. Thus, the reproduction speed or the recording speed by the tape driving device  3  can be coincided with the transmission speed of the network.

TECHNICAL FIELD

The present invention relates to a video tape recording/reproducingdevice for recording video data on a video tape and reproducing thevideo data recorded on the video tape.

BACKGROUND ART

In recent years, video servers (or AV (audio and video) servers) whichperform nonlinear recording and reproduction by using a randomaccessable recording medium have come into widespread use in place ofsequential (linear) recording and reproduction using a VTR tape. Ingeneral, in order to comply with demands for high image quality andsound quality, a video server employed as an equipment in thebroadcasting station is required to achieve a high data transfer rateand a large storage capacity for enabling long-time data recording.Thus, material data composed of a plurality of audio-video data aredispersely recorded by using the RAID (Redundant Arrays of InexpensiveDisks) which is comprised of multiple hard disks adapted fortime-division recording and reproduction and performs multi-channelsimultaneous transmission or multi-channel reproduction of the samematerial data with lag of the reproduction time. And thereby so-calledVOD (video on demand) and NVOD (near video on demand) have beenrealized.

The video server mentioned above is connected to some other equipment(editor, player, etc) via a network such as LAN (Local Area Network),and provides the audio-video data recorded in a storage device such as ahard disk via said network, or records the audio-video data obtainedfrom an external equipment such as a video tape recording/reproducingdevice using the VTR tape as a recording medium.

In the case of recording the audio-video data on the video tape in thememory device of the video server mentioned above, it is necessary toreceive the video output from the video tape recording/reproducingdevice and to convert the video output into a file recordable in thevideo server. Accordingly, it becomes necessary that the video server isequipped with a VTR control system, a video capture circuit and afunction of conversion into a file. Furthermore, since the audio-videodata from the video tape recording/reproducing device are entered intothe video server at a fixed speed, it is requisite that in order tocapture the audio-video data, all of the data receiving circuit, thefile transferring network and the memory device of the video server forstoring the file should keep operating continuously at a fixed transferspeed respectively without any interruption. Consequently, there havebeen problems in the conventional system, including that the cost isincreased and the specification requirements relative to the network andthe storage device of the video server are rendered stricter.

Furthermore, in the video tape recording/reproducing device according tothe conventional technology, if the audio-video data are to betransmitted at a slow speed asynchronous transmission, the audio-videodata are written in the external memory device such as the hard disk atthe fixed speed once and then the data are transmitted asynchronouslyfrom the hard disk. And such external memory devices have led to thecost increase.

Moreover, in the video tape recording/reproducing device, since itbecomes necessary to have a list of files in advance in order totransfer the file to the other terminal on the network. However, in thevideo tape recording/reproducing device, since the video tape is asequential access recording medium, it took time for forming, detectingand referring to such list.

DESCRIPTION OF THE INVENTION

It is therefore an object of the present invention to provide a videotape recording/reproducing device capable of alleviating thespecification requirements and diminishing the load on the network andthe video server.

In order to achieve the object mentioned above in recording the videodata on a video tape and reproducing the video data recorded on thevideo tape, the video tape recording/reproducing device according to thepresent invention defined in claim 1, comprises a driving means forexecuting reproduction and recording of the video data while moving thevideo tape at the predetermined running speed; a buffer memory fortemporarily holding the video data to be reproduced by said drivingmeans or the video data to be recorded; an interface for asynchronouslytransferring the video data between the external equipment and thebuffer memory; and a driving control means for controlling the runningspeed of video tape by said driving means according to the quantity ofdata stored in said buffer memory.

Moreover, as a preferred embodiment such as described in Claim 2, in thevideo tape recording/reproducing device according to Claim 1, thedriving control means controls the running speed of said video tape bysaid driving means, and when the data quantity stored in the buffermemory is larger than the proper value, it controls said driving meansto lower the running speed of said video tape. While, when the dataquantity stored in the buffer memory is smaller than the proper value,it controls said driving means to increase the running speed of saidvideo tape.

Furthermore, as another preferred embodiment, such as described in Claim3, in the video tape recording/reproducing device according to Claim 1,said driving control means controls the driving means so that the motionof the video tape is brought to a stop temporarily when the quantity ofdata stored in the buffer memory is dropped lower than the proper value,and afterwards, when the quantity of data stored in the buffer memory isincreased over the proper value, the motion of the video take is resumedto restart the recording on the video tape.

Furthermore, as another preferred embodiment, such as described in Claim4, in the video tape recording/reproducing device according to Claim 3,said driving control means controls said driving means so that saidvideo tape is returned by the fixed distance in the opposite directionso as to be ready for restarting the next recording after the motion ofthe video tape is temporarily brought to a stop.

As a further preferred embodiment, such as described in Claim 5, thevideo tape recording/reproducing device according to Claim 1, comprisesa memory read and write means for reading out the contents memorized inthe memory means attached to said video tape to memorize the informationthat controls the contents recorded on said video tape and forconducting the write-in, and receives/transmits the managementinformation to be memorized by the memory means via the interface.

In order to achieve said object, the video tape reproducing device forreproducing the video data recorded on the video tape, according to theinvention described in Claim 6, comprises a driving means forreproducing the video data by moving said video tape at thepredetermined running speed, an interface for synchronously transferringthe video data between the buffer memory in which the video data to bereproduced by said driving means is temporarily stored, and a drivingcontrol means for controlling the running speed of said video tape bysaid driving means according to the quantity of data stored in saidbuffer memory.

Furthermore, as another preferred embodiment such as described in Claim7, the video tape reproducing device according to Claim 6, wherein saiddriving control means controls the running speed of said video tape bysaid driving means, and controls said driving means so that when thedata quantity stored in said buffer memory is larger than the propervalue, the video tape running speed is lowered, while when the dataquantity stored in said buffer memory is smaller than the proper value,the video tape running speed is increased.

Moreover, as another preferred embodiment such as described in Claim 8,the video tape reproducing device according to Claim 6, comprises amemory read-out means for reading out the memorized contents of thememory means attached to said video tape in order to memorize theinformation to control the contents recorded on said video tape; andoutputs management information stored in the memory means via theinterface.

According to the present invention, the video data to be reproducedwhile the video tape is being moved by the driving means are storedtemporarily in the buffer memory and then delivered to an externalequipment via the interface. Or the video data put in from the externalequipment via the interface are stored temporarily in the buffer memoryand then the video data are recorded on the video tape to be moved bythe driving means. At this point, the driving control means controls thevideo tape transfer rate by said driving means in accordance with thedata quantity stored in the buffer memory. Accordingly, thereproduction/recording of the video data can be performed by automaticadjusting the tape driving speed according to the transmission speed ofthe network without using any external memory device such as a harddisk. Thereby, it becomes possible to alleviate the specificationrequirements and diminish the load of the network and the video server.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the construction of a taperecording/reproducing device according to the embodiment of the presentinvention.

FIG. 2 is a diagram showing the layout of a magnetic head on therotation drum according to the embodiment of the present invention.

FIG. 3 is a diagram showing the recording pattern formed on the videotape by the magnetic head according to the embodiment of the presentinvention.

FIG. 4 is a diagram showing the trackings by 2 reproduction magneticheads according to the embodiment of the present invention.

FIG. 5 is a conceptual diagram showing the relationship between thebuffer usage rate and the tape speed in a reproduction mode according tothe embodiment of the present invention.

FIG. 6 is a conceptual diagram showing the relationship among thenetwork transfer speed, the buffer usage rate and the tape speed in arecording mode according to the embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to the accompanying drawings an embodiment of the presentinvention will be described in detail in the following paragraphs.

A. CONSTRUCTION OF EMBODIMENT

FIG. 1 is a block diagram showing the construction of a video taperecording/reproducing device according to the embodiment of the presentinvention. In FIG. 1, a tape driving device 3 comprises a tape drivingunit 301 for driving the running of the video tape 8 and a signalrecording/reproducing unit 302 for conducting the recording and/orreproduction of audio-video data onto the video tape 8 by means of amagnetic head 1 placed on the rotation drum 2. This tape driving device3 runs the video tape 8 at the running speed under the control of thetape driving controller 7 and records/reproduces the audio-video data.

The tape driving unit 301 of the tape driving device 3 drives therotation of a supply reel motor to rotate the supply reel of the videotape 8, a take-up reel motor to rotate and drive the take-up reel, and acapstan motor for rotating/driving the capstan which is attached to thevideo tape 8 and moves the video tape 8 under the control of the tapedriving controller 7 so that the video tape 8 runs at the same speed ofthe recording time of the speed becomes larger than the recording timefrom the stop. In this connection, the video tape 8 is driven by thetape driving unit 301 in both directions, i.e., in the same tape runningdirection as in the recording mode (forward direction running) and inthe opposite direction to the recording mode time (reverse directionrunning).

In the recording mode, the signal recording/reproducing unit 302 of thetape driving device 3 adds error correction codes to the signal byapplying the error correction coding using the Reed-Solomon coding tothe signal from the signal processing circuit 4. Furthermore, the signalrecording/reproducing unit 302, after adding sync data and ID data tosaid signal, forms channel coded serial data, and records this on thevideo tape 8 by means of the magnetic head 1.

Furthermore, in the reproduction mode, applying the opposite processingto the recording mode onto the video data read out by the magnetic head1, the signal recording/reproducing unit 302 transmits the video data ofwhich errors are corrected to the signal processing circuit 4.

FIG. 2 shows the construction of a magnetic head 1 placed in the signalrecording/reproducing unit 302 of the tape driving device 3. Themagnetic head 1 comprises a pair of recording heads having differentazimuths each other RECA, RECB, and reproduction heads of which azimuthsconform to the recording heads RECA, RECB; PBA1, PBA2, PBA3, PAB4, PBA5,PBA6, PBA7, PBA8, PBB1, PBB2, PBB3, PBB4, PBB5, PBB6, PBB7, PBB8, and anerase head EH and a dummy head DH. These heads are placed on therotation drum 2 respectively.

In magnetic heads 1, PBAs and PBBs of the reproduction head are combinedas a pair, such as (PBA1 and PBA2, PBA3 and PBA4, PBA5 and PBA6, PBA7and PBA8 corresponding to the track having the azimuth A, and PBB1 andPBB2, PBB3 and PBB4, PBB5 and PBB6, PBB7 and PBB8 corresponding to thetrack with the azimuth B), and are arranged.

In these pairs of reproduction heads, the heads attached with oddnumbers are the preceding side of the drum rotating direction, and theheads attached with even numbers are the succeeding side. The head ofthe preceding side and the head of the succeeding side are separated forone track, i.e., these are placed at intervals of one track pitch.Because of such head arrangement, the tape driving device 3 can conductthe variable-speed reproduction.

FIG. 3 shows a recording pattern formed on the video tape 8 by means ofthe tape driving device 3. The video data to be recorded is an exampleof the 525/60 television signal system.

The track with the azimuth A is formed by the recording head RECA, andthe track with the azimuth B is formed by the recording head RECB.

Video data are recorded in the video recording areas VIDEO 1, 2, andaudio data are recorded in the audio recording areas AUDIO 1, 2, 3, 4.And SYSTEM DATA are recorded in two system data recording areasrespectively.

In this connection, the compression coding according to the MPEG2 isconducted in the signal processing circuit 4, and the signalrecording/reproducing unit 302 records the video data to be formed bythe compression coding on 10 tracks per 1 GOP.

Moreover, the auxiliary data are recorded on the AUX data track of thelongitudinal track on the video tape 8, and control signal to be usedfor the tape running servo is recorded on the control track, and thetime code that is the position information of video data recorded isrecorded on the time code track.

Incidentally, the tape driving device 3 can reproduce the video tape 8at the tape running speed by the control of the tape driving controller7, i.e., can conduct the variable-speed reproduction. Thisvariable-speed reproduction is not the method to displace thereproduction head in the direction orthogonal to the head scanningdirection corresponding to the increase or decrease of the tape runningspeed and to track, nor the method to track changing the rotating speedof the rotation drum corresponding to the increase or decrease of thetape running speed, but is the method of non-tracking to be described inthe following paragraphs and all data on the track can be reproducedeven in the variable-speed reproduction.

The disposition of the reproduction head and the head scanning conditionwill be shown in FIG. 14. Two reproduction heads (PBA1 and PBA2 in Fig.)with the same azimuth as a track (the track T2 with the azimuth A inFig.) are provided on said track having the distance for one trackbetween. In the variable-speed reproduction mode, even if trackings ofthese 2 heads are separated, one of these 2 heads always compensates theother. Thus, a pair of reproduction heads can reproduce all data on thetrack regardless where they are on the track.

The tape driving device 3 possesses 4 sets of pair of reproduction headsfor tracks of azimuth A and B respectively. Thus, the tape drivingdevice 3 can conduct the variable-speed reproduction with the taperunning speed of 0 to +4 times of the recording mode under the controlof the tape driving controller 7. In this connection, the running speedrange in which variable-speed reproduction can be conducted can bechanged by providing the fixed number of reproduction head pairs. In thereproduction mode, the signal processing circuit 4 supplies audio-videodata from the tape driving device 3 to the buffer memory 5 aftercompressing the audio-video data according to the known MPEG2 highefficiency coding method. On the other hand, in the recording move, thesignal processing circuit 4 supplies the audio-video data stored in thebuffer memory 5 to the tape driving device 3.

In a reproduction mode, the buffer memory 5 stores the compressedaudio-video data supplied from the signal processing circuit 4.Meanwhile in a recording mode, the buffer memory 5 stores theaudio-video data supplied from an external equipment via a LAN interface6. The buffer memory 5 has a function of counting the rate of the dataquantity to the entire memory capacity (hereinafter referred to asbuffer usage rate) and sending this rate to the tape driving controller7. The LAN interface 6 sends the audio-video data stored in the buffermemory 5 to the external equipment connected on the network, while itsupplies the audio-video data from the external equipment to the buffermemory 5. Since the MPEG system is adopted for data compression, datawill be handled in units of GOP (Group of Pictures) in each block.

The tape driving controller 7 controls the tape driving speed of thetape driving device 3 in accordance with the buffer usage rate in orderto move the buffer usage rate closer to the proper value. Morespecifically, when the buffer usage rate is larger than the proper valuein the reproduction mode, the tape driving controller 7 lowers the tapedriving speed corresponding to the excess and the time change ratethereof. On the other hand, if the buffer usage rate is smaller than theproper value, the tape driving controller 7 controls the tape drivingdevice 3 to increase the tape driving speed corresponding to thedeficiency and the time change rate thereof. In the recording mode, thetape driving controller 7 stops the tape driving temporarily when thebuffer usage rate becomes lower than the proper value, and then returnsthe tape by the fixed distance in the opposite direction so as to beready for restarting the next recording. While, if the buffer usage ratebecomes larger than the proper value, the tape driving controller 7controls the tape driving device 3 to resume the tape driving andrestart recording on the video tape.

The buffer memory 9 is a memory in which a list of video contentsrecorded on the video tape 8 is recorded, and this memory is provided inthe cassette in which the video tape 8 is stored. The list informationof the buffer memory 9 is read/written by the memory read/write rotation10 and is received between other equipment connected to the network 11via the LAN interface 6.

B. OPERATION OF EMBODIMENT

Next, the operation of the embodiment described above will be explainedin the following paragraphs.

Firstly, the operation in the case of reproducing the contents of videotape and transmitting via the LAN interface 6 will be explained. Whenthe video tape is reproduced by the tape driving device 3, signals readin (audio-visual signals) are supplied to the signal processing circuit4 and outputted as compressed video signals. At this point, even if thevideo tape is driven more slowly than in the recording mode and themagnetic head 1 is kept scanning the same recording track on the videotape repeatedly, the signal processing circuit 4 would not output thesame signal twice or more.

In the signal processing circuit 4, the audio-video data are transmittedcollectively in units of GOP to the buffer memory 5. Since in the tapedriving device 3 the data of each GPO are recorded in a plurality ofhelical tracks as long as the video tape is moving in the samedirection, the data of the same GOP would not be put out twice even ifthe running speed is slow. Thus, the compressed video signals reproducedfrom the video tape will be stored in the buffer memory sequentially incorrect orders without excess or deficiency. The contents of the buffermemory 5 will be transmitted in the order stored via the LAN interface4, and the audio-video data transmitted will be erased from the buffememory 5.

In the process of data reproduction mentioned above, the buffer usagerate is counted in the buffer memory 5 and is supplied to the tapedriving controller 5. When the buffer usage rate is larger than theproper value, the tape driving controller 7 lowers the tape drivingspeed corresponding to the excess and time change rate. On the otherhand, if the buffer usage rate is smaller than the proper value, thetape driving controller 7 raises the tape driving speed according to thedeficiency and the time change rate thereof. More specifically, in thecase where the data transmission speed in the network is low, the bufferusage rate tends to be bigger. Accordingly, delaying the data storage inthe buffer memory 5 by decreasing the tape driving speed, the overallprocessing speed can be adjusted to the transmission speed of thenetwork. On the other hand, when the data transmission speed in thenetwork is fast, the buffer usage rate tends to be smaller. Therefore,increasing the data storage speed by increasing the tape driving speed,the overall processing speed can be adjusted to the data transmissionspeed of the network.

FIG. 5 is a conceptual diagram showing the relationship between thebuffer usage rate and the tape speed in the reproduction mode. As shownin this diagram, the buffer usage rate increases rapidly with the riseof the tape driving speed. The buffer usage rate can be kept properly bydetecting said buffer usage rate and by controlling the feedback todecrease the tape driving speed. Thus, according to this embodiment, theaudio-video data can be transmitted through automatic adjustment of thetape driving speed corresponding to the data transmission speed in thenetwork without using any external storage device such as a hard diskdevice.

Next, the operation in the case of recording the data to be entered viathe LAN interface 6 onto the video tape will be explained as follows.When recording the data on the video tape, contrary to the operationdescribed above, the audio-video data transmitted via the LAN interface6 are temporarily stored in the buffer memory 5. The audio-video dataare transferred to the signal processing circuit 4 from the buffermemory 5 in units of GOP. In the signal processing circuit 4, theaudio-video data are converted into signals recordable on the videotape, and then are recorded on the video tape to be driven at thepredetermined tape driving speed by the tape driving device 3. In thecase of recording on the video tape, the recording head should trace therecording tracks conforming to the format. Therefore, in the recordingmode according to this embodiment, the video tape is driven at thestandard speed.

At this point, if the transmission speed in the network is slow, therecording is done at a higher speed, so that the buffer usage ratebecomes smaller than the proper value. Therefore, the tape drivingcontroller 7 stops the tape driving temporarily, and then returns thetape by the fixed distance in the opposite direction so as to be readyfor restarting the next recording. And when the buffer usage ratebecomes larger than the proper value, the tape driving controller 7resumes the tape driving and records the signal on the video tape.

FIG. 6 is a conceptual diagram showing the relationship among thetransfer speed in the network, the buffer usage rate and the tape speedin the recording mode. If the transfer speed of the network is high, thebuffer usage rate rapidly increases. When the buffer usage rate reachesto the fixed value, the video tape is moved and signals will berecorded. Thus, the buffer usage rate becomes low. And when the bufferusage rate is declined to the fixed value, the video tape is brought toa stop and after being returned by the fixed distance in the oppositedirection, the tape is stopped to be ready for the next recording. Thereason for making the tape run in the opposite direction for the fixeddistance is that in consideration of the non-recording distance until asteady tape speed is attained. And when the buffer usage rate becomesthe fixed value, the video tape is driven again to restart the recordingafter the steady speed is attained. Thus, according to this embodiment,the data can be recorded through the automatic adjustment of the taperunning seed corresponding to the transmission speed of the networkwithout using the external memory device such as a hard disk.

Furthermore, in the video tape recording/reproducing device, a list ofrecording contents of the video tape 8 is required in the case oftransmitting the video data recorded on the video tape 8. However, sincethe video tape is a recording medium of sequential accessing, the wholevideo tape 8 should be reproduced in order to make a list, aconsiderable time is required for preparing such a list. According tothis embodiment, the video tape 8 is equipped with a small capacitynon-contact type buffer memory 9 (a drive circuit to control the buffermemory 9 is included in said buffer memory 9) and memorizes a listaccording to the recording contents of the video tape 8, and alsoequipped with a memory read/write circuit 10 to conduct the non-contactread/write to the buffer memory 9.

The list memorized in the buffer memory 9 is read out by the memoryread/write circuit 10 when the tape driving device 3 reproduces thevideo tape 8 and outputted onto the network 11 via the LAN interface 6.With this arrangement, other terminals on the network can momentarilydetect and refer to the recorded contents of the video tape 8 reproducedby the video tape recording/reproducing device. Moreover, when the tapedriving device 3 records the video data transmitted from the network 11,the list information received from the LAN interface 6 is written in thebuffer memory 9 by the memory read/write circuit 10 and the list of thebuffer memory 8 will be updated. Thus, the list of the buffer memory 9is constantly corresponded to the recording contents of the video tape8.

According to the present invention, when the video data reproduced fromthe video tape being moved by the driving means are held temporarily inthe buffer memory and sent out to the external equipment via theinterface, or when the video data entered from the external equipmentvia the interface are held temporarily in the buffer memory and thenrecorded on the video tape moved by the driving means, the video taperunning speed is controlled by the driving means in accordance with thedata quantity stored in the buffer memory by the driving control means.As a result, the video data can be reproduced or recorded throughautomatic adjustment of the tape driving speed according to thetransmission speed of the network without using any external memorydevice such as a hard disk. Consequently, an advantage in alleviatingthe specification requirements and diminishing the load on the networkand the video server can be obtained.

Furthermore, according to the present invention, when the data quantitystored in the buffer memory is larger than the proper value, saiddriving control means decreases the video tape running speed. While,said driving control means increases the video tape driving speed whenthe data quantity stored in the buffer memory is smaller than the propervalue. As a result, an advantage that the video data can be reproducedby automatically adjusting the tape driving speed according to thetransmission speed of the network without using any external memorydevice such as hard disk device can be obtained.

According to the present invention, when the data quantity stored in thebuffer memory drops lower than the proper value, the driving controlmeans stops temporarily the running of the video tape. And when the dataquantity stored in the buffer memory raises larger than the propervalue, the driving control means resumes the motion of the video tape torestart the recording onto the video tape. As a result, an advantagethat the video data can be recorded through automatic adjustment of thetape driving speed corresponding to the data transmission speed in thenetwork without using the external memory device such as a hard disk canbe obtained. Accordingly, an advantage in alleviating the specificationrequirements and diminishing the load on the network and the videoserver can be obtained.

Furthermore, according to the present invention, after the motion of thevideo tape is stopped temporarily, the video tape is returned by thefixed distance in the opposite direction by said driving control meansto be ready for restarting the next recording. As a result, the videodata recording can be restarted after the video tape running speed isstabilized.

Furthermore, according to the present invention, an advantage that thevideo data recorded on the video tape can be detected and referredwithout any reproduction/recording operation of the video tape by usingthe read/write means of the memory means attached to memorize theinformation for controlling the video data recorded on said video tapecan be obtained.

INDUSTRIAL UTILIZATION

The video tape recorder according to the present invention can be usedto the video server employed as an equipment of the broadcastingstation.

1. A video tape recording/reproducing device for recording video data ona video tape and reproducing the video data recorded on the video tape,comprising: driving means for driving the video tape at a predeterminedrunning speed; a rotatable drum having a plurality of magnetic heads forexecuting reproduction and recording of the video data from/to the videotape; a buffer memory for temporarily holding the video data to bereproduced by said heads or the video data to be recorded, counting arate of change of a current data quantity stored in the buffer memory toan entire memory capacity, and supplying the rate of change to a drivingcontrol means; an interface for asynchronously transmitting the videodata between an external equipment and said buffer memory; and drivingcontrol means for controlling the running speed of said video tape bysaid driving means in accordance with the current data quantity storedin said buffer memory and the rate of change of the current dataquantity stored in the buffer memory to the entire memory capacity, bothsupplied from the buffer memory, wherein a range of the running speed isa function of a fixed number of the plurality of heads; whereby thevideo data is recorded on the video tape in the form of multiple tracks;whereby the magnetic heads are arranged in pairs, the heads in each pairare spaced apart by about one track width, and the heads in each pairhave about the same azimuth angle; whereby said device is operable toperform a variable speed reproduction in which all of the video datarecorded on the video tape is reproduced by changing the tape runningspeed without changing the drum rotation speed; and whereby the videotape is housed within a cassette that includes a non-contact type buffermemory for storing a list of contents of the video tape, the non-contacttype buffer memory including a drive circuit for controlling saidmemory, being read when data is reproduced from the tape and beingwritten when data is recorded to the tape.
 2. A video taperecording/reproducing device as defined in claim 1, wherein: saiddriving control means controls the running speed of said video tape; andsaid driving control means is controlled in such a manner that, when thedata quantity stored in said buffer memory is larger than apredetermined value, the video tape running speed is lowered, while whenthe data quantity stored in said buffer memory is smaller than thepredetermined value, the tape running speed is increased.
 3. A videotape recording/reproducing device as defined in claim 1, wherein: saiddriving control means controls said driving means in such a manner that,when the data quantity stored in said buffer memory becomes lower than apredetermined value, the running of said video tape is suspendedtemporarily, while when the data quantity stored in said buffer memorybecomes higher than the predetermined value, the motion of said videotape is started again in order to restart the recording on the videotape.
 4. A video tape recording/reproducing device as defined in claim3, wherein: said driving control means controls said driving means sothat the video tape is returned by a fixed distance in the oppositedirection to be ready for restarting the next recording after therunning of said video tape is temporarily brought to a stop.
 5. A videotape recording/reproducing device as defined in claim 1, comprising:memory write/read means for reading out the recorded contents of thememory means attached to said video tape in order to memorize theinformation to control the contents recorded on said video tape and forwriting these.
 6. A video tape reproducing device for reproducing thevideo data recorded on a video tape, comprising: driving means fordriving said video tape at a predetermined running speed; a rotatabledrum having a plurality of magnetic heads for executing reproduction ofthe video data from the video tape; buffer memory for temporarilyholding the video data to be reproduced by said heads, counting a rateof change of a current data quantity stored in the buffer memory to anentire memory capacity, and supplying the rate of change to a drivingcontrol means; an interface for asynchronously transmitting the videodata between an external equipment and said buffer memory; and drivingcontrol means for controlling the running speed of said video tape bysaid driving means corresponding to the current data quantity stored insaid buffer memory and the rate of change of the current data quantitystored in the buffer memory to the entire memory capacity, both suppliedfrom the buffer memory, wherein a range of the running speed is afunction of a fixed number of the plurality of heads; whereby the videodata is recorded on the video tape in the form of multiple tracks;whereby the magnetic heads are arranged in pairs, the heads in each pairare spaced apart by about one track width, and the heads in each pairhave about the same azimuth angle; whereby said device is operable toperform a variable speed reproduction in which all of the video datarecorded on the video tape is reproduced by changing the tape runningspeed without changing the drum rotation speed; and whereby the videotape is housed within a cassette that includes a non-contact type buffermemory for storing a list of contents of the video tape, the non-contacttype buffer memory including a drive circuit for controlling saidmemory, being read when data is reproduced from the tape and beingwritten when data is recorded to the tape.
 7. A video tape reproducingdevice as defined in claim 6, wherein: said driving control meanscontrols the running speed of a video tape by said driving means; andsaid driving control means controls said driving means such that whenthe data quantity stored in said buffer memory is larger than apredetermined value, the running speed of said video tape is decreased;and when the data quantity stored in said buffer memory is smaller thanthe predetermined value, the running speed of said video tape isincreased.
 8. A video tape reproducing device as defined in claim 6,comprising: memory readout means for reading the recorded contents ofthe memory means attached to said video tape to memorize the informationto control the contents recorded on said video tape.